Duplex translating-circuits



J. R. CARSON.

DUPLEX TRANSLATING CIRCUITS.

APPLICATION FILED MAR. 26. 1911. RENEWED MAY 27.1919.

1,343,307. Patented June 15, 1920.

INVENTOR John 12 Carsan /Zwtojww ATTRNEY UNITED STATES *PArsNr OFFICE.

JOHN R. CARSON, OF MONTGLAIR, NEW JERSEY, ASSIGNOR T0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

DUPLEX TRANSLATING-CIRCUITS.

Specification of Letters Patent.

Patented June 15, 1920.

Original application filed September 5, 1916, Serial No. 118,573. Divided and this application filed March 26, 1917, Serial No. 157,413. Renewed May 27, 1919.

To all whom it may concern:

Be it known that I, JOHN R. (Larson, residing at Montclair, in the county of Essex and State of New Jersey, have invented certain Improvements in Duplex Translating- Circuits, of which the following is a speclfication.

The invention of this application, which is a division of application Serial No. 11857 3, filed September 5th, 1916, relates to signaling circuits, and has for its general object, the provision of a duplex translating system which is capable of a wide range of utility, and which shall exhibit a high de gree of efficiency in the various applications of which it is capable.

In its general. embodiment the invention comprises a duplex translating structure having a pair of input and a pair of output circuits, the pair of input circuits being symmetrically associated with one source of current variation, and oppositely associated with a second source, the output circuits being differential with respect to one outgoing or receiving circuit and cumulative with respect to another outgoing circuit. Thus the first mentioned source produces by virtue of its symmetrical connections potential fluctuations of the same phase in the two input circuits, while the second mentioned source, by virtue of the fact that the input clrcuits are oppositely associated therewlth, produces potential fluctuations of opposlng phase in said input circuits. This statement is made to define the significance attached to symmetrical and opposite connections in this specification.

Thus in general there may be four main elements comprising two sources and two receiving circuits which may be variously related to the translating device proper. Additional results may be produced by the omission of one or more of the four main elements, with corresponding changes in the connections of the remaining elements. The form of translating device used may preferably be of the thermionic vacuum tube type, though this invention is not limited to any particular type of translating device. It will be understood that the term trans lating device embraces broadly an apparatus or relay capable of amplification, detection or modulation of signal waves.

In its more specific aspects the invention Serial No. 300,179.

has for one of its objects the provision of a translating circuit whereby it is possible to modulate high frequency or carrier currents by low frequency signaling currents, the carrier currents being suppressed except at such time as low frequency signaling currents are applied to the circuit. Such a structure is capable also of functioning, in combination with a local source of high frequency energy, as an improved detector in which distortion is largely eliminated. The invention will be more fully understood by reference to the drawing in which Figure l is a diagram of modulating system for high frequency carrier wave signaling, in which the carrier current used for transmission is suppressed except when modulated at low frequency, the modulating device employed being of the thermionic type. Fig. 1 shows a single duplex tube. Fig. 2 is a diagram of a similar circuit, using a me chanical repeater for the same purpose. Referring now to Fig. 1, a pair of three element thermionic tubes having filaments 1, 2, grids 3, 1, and plates 5, 6 are provided, the filaments being heated by-.a battery 7. The tubes are preferably similar and equal in their structure and characteristics. They are then equivalent to and may be replaced as illustrated in Fig. l by a single duplex tube, such as is shown in patent of E. H. Colpitts, No. 1128292, February 16th, 1915. The input circuits of the tubes are arranged in parallel with respect to the secondary winding of an induction coil 41, which is arranged in the common conductor of the two input circuits, the primary of said induction coil being arranged in circuit with a source of current variations 10. Condensers 12 and 13 are inserted in the input circuits and the secondary 415 of a transformer 4.4 is shunted about the two condensers. The primary winding 43 of said transformer is arranged in an incoming circuit 12 leading to a source of low frequency signaling current such, for example, as a telephone transmitter.

The output circuits are also connected in parallel with respect to a battery 17, arranged in the common conductor of said circuits. Each output circuit contains a primary winding of a three-winding transformer 18. The winding in circuit with plate 5 being designated 46, and that corresponding to plate 6 being designated 17 conductor thereof.

ized in windings The secondary winding 49 is connected to an outgoing circuit 5().

Normally, when no currents are impressed upon circuit 42, the high frequency oscillations from source 40 acting through transformer 41 impress equal voltage variations of the same phase upon grids 3 and 4, thereby producing equal fluctuations of the same phase in the output circuits. Coils 46 and 47 being Wound in the same direction, circuit 50 is differentially coupled to the two output circuits, the fluctuations neutralize each other, and no effect is produced on circuit 50. hen, however, low frequency current variations from circuit 42 are impressed upon the repeater circuit through transformer 44, the high frequency potential variations are augmented upon the one grid and decreased upon the other, producing correspondingly augmented fluctuations in the one output circuit and.

correspondingly reduced fluctuations in the other. cuits are no longer balanced and consequently oscillations are produced in the outgoing circuit' 50 which have an amplitude proportionate to the instantaneous value of the low frequency modulating currents coming from circuit 42. It is therefore seen that the carrier waves are suppressed except when signaling currents are applied.

Fig. 2 is an equivalent arrangement using a mechanical repeater instead of thermionic vacuum tubes. In this arrangement two parallel oscillation circuits having variable resistances 51 and 52, and condensers 53 and 54 therein are provided with a common conductor in which is inserted the secondary 55 of a transformer 56, the primary 57 of which is in circuit with a source of high frequency oscillations 40. Primary windings 46 and'47 of a transformer 48 are also included in the circuits, While the secondary 49 is connected to outgoing circuit 50. A "mechanical repeater comprising a receiver coil 58 and a differential or push and pull microphone isprovided, the receiver coil 58 being in a circuit 42 leading to a source of low frequency modulating or signaling currents, and the electrodes 59 and 60 of the microphone being connected in the two oscillation circuits, with the common electrode 61 connected to the common High frequency oscilla- 40 are normally neutral- 46 and 47. lVhen however modulating currents flow in circuit 42, the receiver 58 acts to correspondingly vibrate theelectrode 61, so that the resistance tions from source in one circuit is increased and in the other is decreased, with the result that the oscillations in the one circuit are increased while those in the other circuit are simultaneously decreased. The oscillations are therefore no longer balanced in windings 46 and 47 The fluctuations in the output cir-.

and consequently oscillations are impressed upon circuit 50 through transformer 48, having an amplitude proportional to the incoming low frequency currents of circuit 42.. It will be seen from this that the mechanical repeater is equivalent to the thermionic tube modulator of Fig. 1, and it will be understood that the arrangement is not restricted to any particular type of trans lating or modulating device.

It will be seen that by this invention a duplex translating system has been devised which is both simple and ei'licient and which is capable of a large number of applications to produce widely varying results. While the invention has been illustrated as embodied in a limited number of forms it will be understood that the embodiment may be widely varied without departing from the scope of the appended claims.

lVhat is claimed is:

1. A modulating system comprising a pair of translating devices, a source of high frequency energy similarly connected with said devices, a source of modulating energy oppositely connected with said devices and an outgoing circuit differentially coimected with said devices.

2. A modulating system comprising a dnplex translating arrangement having two symmetrical sections, a source of high frequency energy similarly associated with said two sections, a source of modulating energy oppositely associated with said two sections and an outgoing circuit differentially associated with said two sections.

A modulating system comprising a pair of translating devices having input and divided output circuits, a circuit containing a source of high frequency energy, a circuit containing a source of low frequency modulating energy, one of said circuits being symmetrically associated with said input circuits and the other being oppositely associated with said input circuits and an output circuit differentially associated with said output circuits.

4. A modulating system con'iprising a duplex translating arrangement having divided input and divided output circuits, a source of high frequency energy symmetrically associated with said input circuits, a source of modulating energy oppositely associated with said input circuits and an outgoing circuit differentially associated with said output circuits.

5. In a transmitting apparatus, a pair of translating devices comprising a common conductor and individual sections, a source of sending energy associated with the common conductor, an outgoing circuit difi'erentially associated with the translating devices, whereby the sending energy is normally balanced with respect to the outgo' ing circuit, and a source of modulating energy serially associated with the individual sections, whereby the sending energy is unbalanced with respect to the outgoing circuit when the modulating energy is applied.

6. In a transmitting apparatus, a duplex repeating arrangement comprising a pair of input and a pair of output circuits, each pair of circuits having a common conductor, a source of sending energy associated with the common conductor of the input circuits, an outgoing circuit diiferentially associated with the output circuits, whereby the effect of the sending energy in the output circuits is normally balanced with respect to the outgoing circuit, and a source of modulating energy serially associated with the input circuits, whereby the effect of the sending energy is unbalanced when the modulating energy is applied.

7. A translating apparatus comprising a duplex translating arrangement including a common path and individual paths, a plu rality of independent circuits, one of said independent circuits comprising a source of high frequency oscillations, another of said independent circuits comprising a source of modulating variations and another of said independent circuits comprising an outgoing circuit, one of said independent circuits being associated with said common path and the other of said independent circuits being associated with said individual paths.

8. A translating apparatus comprising a duplex translating arrangement, parallel circuits for said translating arrangement including a common path and individual paths, conductive evacuated gaps in said individual paths, a source of high frequency oscillations and a source of modulating signal variations associated with said circuits, one of said sources being associated with said circuits through said common path.

9. A translating apparatus comprising a duplex translating arrangement, parallel circuits for said translating arrangement including a common path and individual paths, conductive evacuated gaps in said individual paths, a source of high frequency oscillations and a source of modulating signal variations associated with said circuits, one of said sources being associated with said circuits through said common. path and the other of said sources being associated with said circuits through said individual paths.

10., A translating apparatus comprising a duplex translating arrangement, parallel circuits for said translating arrangement including a common path and individual paths, conductive evacuated gaps in said individual paths, a plurality of independent circuits comprising a source of high frequency oscillations, a source of modulating signal variations and an outgoing circuit, one of said independent circuits being associated with said parallel circuits through said common pat 11. A translating apparatus comprising a duplex translating arrangement, parallel circuits for said translating arrangement including a common path and individual paths, conductive evacuated gaps in said individual paths, a plurality of independent circuits comprising a source of high fre quency oscillations, a source of modulating signal variations and an outgoing circuit, one of said independent circuits being associated with said parallel circuits through said common path and the others of said independent circuits being associated with said parallel circuits through said individual paths.

12. A modulating apparatus comprising a pair of translating devices, a source of sending energy and an outgoing circuit, said source being so connected that its effect shall be normally balanced with respect to the outgoing circuit, and a source of modulating signal current so connected to the translating devices as to unbalance the effect of the sending energy when the modulating signal energy is applied.

13. A transmitting apparatus for carrier wave signaling systems comprising a modulating arrangement having an input and an output circuit for translating low frequency signal oscillations into high frequency carrier oscillations, a circuit to supply signal oscillations to said modulating arrangement, and a circuit for supplying high frequency energy to said modulating arrangement, said circuit being so associated with said modulating arrangement that energy from said last mentioned circuit will not react upon said first mentioned circuit or said output circuit when signaling oscillations are not supplied.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses, this 15th day of March, 1917.

JoHN' a. CARSON.

Witnesses:

RALPH W. WOLF, FREDK. S. ROBINSON. 

